Make rle decoder public under experimental feature

[zeevm]

Closes #1270

Are there any user-facing changes?

'rle' decoder is exposed outside the crate.

[alamb]

Thank you for the contribution @zeevm

This is fine with me, though I wonder what your expectation is for the stability of the API within the rle module? I don't think it has changed much recently but it may in the upcoming releases.

What would you think if we made it experimental as a signal that we may change it (meaning you would have to enable the experimental arrow feature )

cc @tustvold @nevi-me @sunchao

[sunchao]

LGTM too, I'd also suggest to consider putting it under experimental flag.

[tustvold]

I think this would be a perfect fit for what the experimental feature flag was created for (#1032) - namely lower-level APIs that may change, and that we don't want to overburden the average user who "just wants to read a parquet file" with the cognitive load of 👍

FWIW I do hope to at some point do a cleanup of some of the lower-level APIs in the parquet crate, in particular a lot of the trait plumbing currently leaks out, but who knows when I'll find time for that 😅

[tustvold]

Perhaps if you're only interested in rle we could make the above modules pub(crate)?

[zeevm]

@tustvold I'd like to use 'decoding' as well, it makes it really easy to decode RLE encoded pages I get from a column page reader.

[tustvold]

Makes sense 👍

[zeevm]

@alamb @sunchao I've changed it to be "experimental" as you suggested.

[zeevm]

What's the process for completing the PR?

[codecov-commenter]

Codecov Report

Merging #1271 (9c1bb05) into master (fa72873) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #1271      +/-   ##
==========================================
- Coverage   83.02%   83.02%   -0.01%     
==========================================
  Files         180      180              
  Lines       52269    52269              
==========================================
- Hits        43398    43396       -2     
- Misses       8871     8873       +2     

Impacted Files	Coverage Δ
arrow/src/array/transform/mod.rs	84.51% <0.00%> (-0.26%)	⬇️
parquet_derive/src/parquet_field.rs	66.21% <0.00%> (ø)

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[zeevm]

@tustvold @alamb @sunchao I'm not too versed in github workflow, is there anything else I should do to complete the PR?

[sunchao]

LGTM, merging to master.